Esters having epoxy groups along their side chains, such as certain epoxidized vegetable oils, are known. See, for instance, U.S. Pat. No. 5,973,082. However, these conventional epoxidized esters have a relatively low reactivity due to the fact that the epoxy groups are internal, i.e. they are present along the side chains of the triacylglceride and not at the ends of the chain. This low reactivity makes these esters unpreferred or even unsuitable for a wide variety of applications.
Accordingly, the art has seen efforts to prepare esters having terminal epoxy groups. For instance, WIPO Publication 00/18751 (“WO 00/18751”) discusses an epoxy obtained by first reacting trimethylolpropane with 10,11-undecenoic acid and by subsequently epoxidizing the unsaturated groups of the thus obtained ester using an oxidizing agent. In example 5 of this publication, a composition comprising the exemplified epoxy ester, isophorone diamine, and fairly large amounts of bisphenol A diglycidyl ether is cured. Although the exemplified epoxy ester of WO 00/18751 may provide improved reactivity when compared to esters having internal epoxy groups, further improvements in reactivity of mixtures comprising the esters are still desired.
Accordingly, aspects of the present invention include improving the cure speed of mixtures comprising epoxy-terminated esters. Other aspects include providing network polymers formed by curing mixtures comprising epoxy-terminated esters, wherein the network polymers have a comparatively high glass transition temperature, excellent UV stability, improved toughness, and/or improved adhesion.